A number of security issues arise when computers or other resources are accessible by humans. Most computers and computer networks incorporate computer security techniques, such as access control mechanisms, to prevent unauthorized users from accessing remote resources. Human authentication is the process of verifying the identity of a user in a computer system, often as a prerequisite to allowing access to resources in the system. A number of authentication protocols have been proposed or suggested to prevent the unauthorized access of remote resources. In one variation, each user has a password that is presumably known only to the authorized user and to the authenticating host. Before accessing the remote resource, the user must provide the appropriate password, to prove his or her authority.
Generally, a good password is easy for the user to remember, yet not easily guessed by an attacker. In order to improve the security of passwords, the number of login attempts is often limited (to prevent an attacker from guessing a password) and users are often required to change their password periodically. Some systems use simple methods such as minimum password length, prohibition of dictionary words and techniques to evaluate a user-selected password at the time the password is selected, to ensure that the password is not particularly susceptible to being guessed. As a result, users are often prevented from using passwords that are easily recalled. In addition, many systems generate random passwords that users are required to use.
In a call center environment, users are often authenticated using traditional query directed authentication techniques by asking them personal questions, such as their social security number, date of birth or mother's maiden name. The query can be thought of as a hint to “pull” a fact from a user's long term memory. As such, the answer need not be memorized. Although convenient, traditional authentication protocols based on queries are not particularly secure. For example, most authentication systems employing this approach use a limited number of questions that are static and factual. Thus, the answers can generally be anticipated and easily learned by a potential attacker. A need therefore exists for an authentication technique that provides the convenience and familiarity of traditional query directed authentication with greater security. A further need therefore exists for a method and apparatus that employs query based passwords having answers that are easy for the user to remember, yet ensures that the answers are not easily guessed by an attacker.